Upgrade Story Part1: A Tale of Two Duets.

 Ok, you've had the teaser, here's the first instalment of the upgrade story that will hopefully explain why i I was installing a new display board for my instruments.

So, There I was a few weeks ago, cruising eBay. Well actually checking my saved searches. I have a permanent search for NASA sailing products. Up popped a Duet display.  

The Duet is one of the most popular of NASA's Clipper displays because it combines a Depth and speed readout. Easily the two most popular readouts used by sailors. Even used Duet units can go for silly money, just because they are so popular.

This Duet unit was a bit worse for wear, missing digits on the LCD display.

Well, if it's dry solder joints I can sort that out and if it's something else..... well if it's cheap enough I won't lose much sleep. It's worth a punt.

It was cheap up until the last few seconds: there's always a sniper on eBay!. I duly won it for £21. Not that cheap. But cheap enough.

It took a few weeks to get around to testing it and unfortunately the problem was corrosion on the pins for the display itself:

Those discoloured pins were the cause. I assume the connection to the LCD in the glass had been destroyed. I tried a few remedies, but none worked. 

Consigned to the parts bin then.

For a month anyway.

Then another popped up on eBay. This one completely broken and described as such on eBay. No display but again, if it was cheap maybe I could repair or make two good 'uns out of the pair of bad 'uns.

I won it for the start price, 99p. No competition thanks to the honest description. So two NASA Clipper Duet units for £22 plus the postage (nobody counts postage on eBay bargains, right?).

So I set to for a second round with the latest unit. Dead as the proverbial dodo.

When I opened it I more or less knew why. 

All that furry stuff over the PCB is the guts of an exploded capacitor. Either over voltage or reverse voltage. But something catastrophic has happened to this unit. 

But no matter, I wasn't that interested in the electronics, the LCD display appeared flawless. No corrosion on the pins. So I dug the old faulty unit out and dismantled it.

The first thing to do was resolder the wires connecting the two PCBs of the unit together. This seems to be a weak spot of the Duet unit as both units had pretty weak connections where the wires are soldered to the PCB. Maybe NASA could put a bit of hot glue on the pcb over the wires to support them. It would help loads.

Here's the Wires, not looking good after a few years. Bad form NASA, you could fix this so easily:

So, two unit in peices, let's get them assembled hopefully into a single working unit.

Here's the creation of Franken-Duet in process:

Anyway, duly resoldered, the LCD displays were swapped over. Then the moment of truth, wuld there be missing digits?

Look here: 

Looks promising, let's wait.

Oh yeah! It works!

So with a bit of ingenuity I have a working NASA duet for £22. Not bad considering even used examples can go as high as £50 on eBay. Just needed some soldering skills and a bit of faith it would work out. Things you definitely need when on a very tight budget.

So, I can now combine the depth and speed sensors into one unit. Which is good, because the next instalment details how I needed to make some space on my instrument board. In actual fact I needed a bigger board.